Some computer networks are configured to support automated deployment of software. For instance, in some web-based deployment systems, when a user working at a networked machine selects a particular icon or a particular URL (Universal Resource Locator), software is automatically downloaded to the user's machine from another machine in the network. The downloaded software may then be installed on the user's machine and run. Installation may place the downloaded software in a temporary location, such as a browser or virtual machine “sandbox” which limits the downloaded software's access to files, for example, as a security measure. Installation may also place downloaded software in a more permanent location such as a local hard drive, where the downloaded software receives security treatment equal to the treatment of software that is installed directly on the user's machine from a CD or DVD, for example. The downloaded software may be a complete application program, for example, or updates which replace some but not all previously installed baseline components of an application program, or a customization of a previously installed application which adds functionality without replacing or modifying the application's baseline components.